Microblog Memes

I'm in solar/BESS, and I mean more and more DER sites are making use of string inverters which break out arrays into greater chunks than with central inverters. With those, you have more granularity of control where you can drop entire blocks/strings at a time to fall to your curtailed export rate.

You might ask yourself though why DERs can't just ramp inverter outputs up or down to match curtailment automatically across a whole site. You can absolutely do that, but what happens is your solar or wind resource stays high on the DC or low frequency (LF) AC side, respectively, while power frequency AC is low on the other side of the inverters. This is referred to as DC:AC ratio in the biz, and the higher that ratio, the more losses your inverters experience and less efficient they are. This also puts a huge strain on your inverters and can lessen their operational lifetime.

But really, DERs tie into the grid at distribution level and so they don't fall under the regulations of FERC & NERC (at least in North America). This means that smaller producers don't have the same requirements for control as do utility-scale players, so the incentive to control these string inverters at that granular level isn't there. It's much easier to just trip the main breaker and wait until the utility gives you the go ahead to turn back on.

I suspect that at lot of producers may want to look into greater control capabilities in the future, but this also depends on inverter OEMs too allowing that control.

I’m adjacent to this problem, so I have a little context, but am not an expert at all.

To my knowledge, we don’t have granular control over panels. So we can shut off legs of a plant, but that’s a lot of power to be moving all at once.

Instead, prices are set to encourage commercial customers to intake more power incrementally. This has a smoother result on the grid, less chance of destabilizing.

A customer like a data center could wait to perform defragmentation or a backup or something until the price of power hits a cheap or negative number.

It is a financial problem. Technically you can just cover the solar panels. But that's not good financially.

It still costs real money to maintain the infrastructure; so even if the power was always free; you would still have to pay something to cover the maintenance costs.

Isn't one the issues with hydrogen motors that they are a bit explodey? Genuine question, haven't looked into it in a long time.